I just came back from executing a Ready assessment for a company in Minnesota, where I analyzed 740,000 lines of code in a VB6 application, of which 660,000 belonged to a single Visual Basic project (.vbp). This is actually the largest single .vbp I have seen so far, beating the previous record of about 500,000 lines of code held by an European company. We have migrated plenty of applications that contain 1+ million lines of code, but they are usually distributed across many .vbp’s.

Though unusual, single vbp’s of this size are perfectly manageable from a migration standpoint, and here are some things that can be done to deal with them:

Ensure that the migration computer has at the very minimum, 3GB of RAM.

Look for customization opportunities before you start migrating the code. Customizing the VBUC for this specific VBP can reduce manual effort drastically.

When making manual changes, start with a small team until you get the project to compile, especially if migrating to VB.NET as the compiler has a maximum of build errors that it can show at any given time.

Once the application compiles, increase the team size and go for Visual Equivalence by distributing the different forms and user controls across your developers.